A palm-sized laser appliance, which looks like a pistol. Not only can it shoot long distances up to 3 miles away, but it can also burn paper outside through a room. The most powerful thing is that it can target objects outside the earth's atmosphere. The power of a general Laser pointer is 0.5mW, which can reach more than ten kilometers away in a clean environment. However, due to the large amount of particles in the air, the scattering and absorption of them will be enhanced. Under normal conditions, only about 500 meters may be completely dissipated, and the visible distance may be only half.
At present, presentations (PowerPoint, PPT) are widely used in education, lectures and conferences. When presenting a presentation, the projection system mainly includes: a projector, a screen and a laser pointer. During the presentation of the PPT, the laser pointer serves as an eye-catching moving spot to point the PPT at a long distance, and has the function of reminding the audience to watch key information.